JP2007335234A - Induction heating cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an induction heating cooker of which normal heating is continued only when temperature can be detected by an infrared ray sensor. <P>SOLUTION: When the illuminance of the surroundings is short, illumination for cooking is lighted, and existence of a cooking container is determined from energy which the infrared ray sensor has received and energy which an illuminance sensor has received. When the cooking container has not been detected by a cooking container detecting means, since the heating control means controls so that the heating of the cooking container is stopped or so that the heating electric power is suppressed, the induction heating device can be realized which is high in safety by preventing the cooking container from becoming a high temperature without detecting the temperature by the infrared ray sensor. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an induction heating device used in general households, restaurants and the like.

  Conventionally, as shown in FIG. 6, this type of induction heating device includes a top plate 2 on which a cooking container 1 is placed, a heating coil 3 disposed below the top plate 2, and a cooking container 1. Infrared sensor 4 arranged facing the bottom, temperature detecting means 5 for converting the received light energy of infrared sensor 4 into temperature, and heating control means for inductively heating cooking vessel 1 by passing a high-frequency current through heating coil 3 8 and. A plurality of infrared sensors 4 may be provided (see, for example, Patent Document 1).

When heating is started, a high frequency magnetic field is generated from the heating coil 3 by a signal from the heating control means 8. The cooking vessel 1 is heated by this high frequency magnetic field and the temperature rises. The temperature of the cooking container 1 is measured by the infrared sensor 4 and converted into a temperature by the temperature detection means 5, and the heating control means 8 controls the heating amount based on the result.
JP 2003-109736 A

  However, in the conventional configuration, when the bottom of the cooking container 1 covers the detection area of the infrared sensor 4, the temperature can be detected correctly, but when the bottom of the cooking container 1 deviates from the detection area of the infrared sensor 4. The infrared energy from the cooking container 1 is reduced and the infrared sensor 4 receives disturbance light such as visible light around the cooking container 1, so that the S / N ratio is deteriorated and the temperature detection error is large. Had the problem of becoming.

  The present invention solves the above-mentioned conventional problems, and whether or not the bottom of the cooking container 1 covers the detection area of the infrared sensor 4 based on the infrared energy received by the infrared sensor 4 and the illuminance around the cooking container 1. If the surrounding illuminance is insufficient and it cannot be accurately determined whether the bottom of the cooking container 1 covers the detection area of the infrared sensor 4, the communication control means turns on the lighting for cooking. By doing so, it is possible to determine whether or not the bottom of the cooking container 1 is covered. If it is not covered, the temperature detected by the temperature detecting means 5 has many errors, and the cooking container 1 becomes hot and ignites. It is an object of the present invention to provide an induction heating apparatus that is controlled so as to stop heating or suppress the amount of heating power so as not to cause an accident such as that, thereby improving safety.

  In order to solve the above-mentioned conventional problems, the induction heating cooker of the present invention is provided with an illuminance sensor for measuring the illuminance around the cooking container, and communication control means for controlling lighting of the cooking light. Is provided.

  By this, when the surrounding illuminance is low, the illumination for cooking is turned on by the communication control means to secure the illuminance, and it is determined whether there is a possibility that energy from other than the cooking container enters the infrared sensor, When it is determined that the infrared sensor is receiving energy from other than the cooking container, it is possible to detect that the cooking container is placed at a position deviated from the detection range of the infrared sensor.

  The induction heating cooker of the present invention can determine whether or not the cooking container is placed in a state where the temperature detection means can correctly detect the temperature even when the ambient illuminance is low, and the temperature cannot be detected correctly. In such a case, control is performed so as to stop heating or suppress the amount of heating power to prevent the cooking container from becoming a high temperature unintended by the user, and an induction heating apparatus with improved safety can be realized. .

  A first invention is a cooking container for heating a cooked food, a top plate on which the cooking container is placed, a heating coil for generating an induction magnetic field to heat the cooking container, and cooking via the top plate An infrared sensor for detecting infrared radiation radiated from the container; temperature detection means for converting the temperature of the cooking container from energy received by the infrared sensor; and an illuminance sensor for detecting illuminance around the cooking container. The cooking container detection means for determining the presence or absence of the cooking container from the energy received by the infrared sensor and the energy received by the illuminance sensor, the heating by the detection result of the cooking container detection means and the temperature information of the temperature detection means Heating control means for controlling the heating power amount of the cooking container by controlling the high-frequency current of the coil, and for cooking for brightly illuminating the cooking place And a communication control means for performing communication and control with the cooking illumination, and when the value detected by the illuminance sensor in the previous period is equal to or less than a predetermined value, the communication control means With the configuration that lights up, even if the ambient illuminance is low, it is possible to detect whether the cooking container is placed at a location deviated from the detection range of the infrared sensor. When it is judged that it cannot be detected, it is possible to prevent the cooking container from becoming too hot as the user does not intend by stopping heating or suppressing the amount of heating power.

  According to a second aspect of the present invention, in particular, in the first aspect of the present invention, when the heating control unit finishes heating the cooking container, the communication control unit turns off the cooking light after a predetermined time has elapsed. Thus, it is possible to avoid unnecessary lighting of the cooking light after cooking is completed and to prevent power consumption.

  In the third invention, in particular, in the first or second invention, when the communication control means does not control the lighting of the cooking illumination, the heating control means finishes heating the cooking container. Even so, it is possible to improve the usability by avoiding inadvertently controlling the cooking lighting against the user's intention by adopting a configuration in which the cooking lighting is not turned off by the communication control means. it can.

  In particular, in the fourth invention, in any one of the first to third inventions, even if the communication control means controls the lighting of the cooking light to be turned on, the value detected by the illuminance sensor is When the value is equal to or lower than the predetermined value, the display means displays that the control by the communication control means is not operating normally, so that the bottom of the cooking container covers the detection area of the infrared sensor. If the heating is started or continued as it is, the temperature detection means cannot detect the correct temperature, and the cooking container is used if the heating control is performed based on the inaccurate temperature information. Since it is dangerous because the temperature is not intended by the person, safety can be improved by notifying that effect.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 shows a schematic configuration diagram of an induction heating apparatus according to a first embodiment of the present invention.

  In FIG. 1, 1 is a cooking container, 2 is a top plate on which the cooking container 1 is placed, 3 is a heating coil disposed below the top plate 2, and 4 is disposed to face the bottom of the cooking container 1. The infrared sensor 5 is a temperature detecting means for converting the temperature from the light reception energy of the infrared sensor 4, 6 is an illuminance sensor for detecting the illuminance around the cooking vessel 1, and 7 is the energy and illuminance received by the infrared sensor 4. Cooking container detection means 8 for discriminating the presence or absence of the cooking container 1 from the energy received by the sensor 6, 8 is a heating control means for inductively heating the cooking container 1 by applying a high-frequency current to the heating coil 3. Reference numeral 9 denotes a cooking lamp, and reference numeral 10 denotes a communication control means for controlling the cooking lamp 9.

  About the induction heating apparatus comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  First, although not shown, when an instruction to start heating is issued to the induction heating device by an operation unit or the like connected to the heating control means 8, the heating control means 8 supplies a high-frequency current to the connected heating coil 3. . The cooking vessel 1 is placed on the top plate 2 above the heating coil 3 and is in a magnetically coupled state with the heating coil 3. A high-frequency magnetic field is generated from the heating coil 3 supplied with the high-frequency current, an eddy current due to electromagnetic induction flows in the cooking vessel 1, and the cooking vessel 1 is heated by the Joule heat.

  The infrared sensor 4 receives infrared rays emitted from the cooking container 1 through the top plate 2, and the information is sent to the temperature detection means 5. The temperature detection means 5 calculates the temperature of the cooking container 1 from the amount of energy received by the infrared sensor 4 and sends the temperature information to the heating control means 8.

  The heating control unit 8 controls the heating power amount designated by the user, while suppressing the heating power amount or stopping the heating depending on the temperature information obtained from the temperature detection unit 5. For example, when the heating operation is started in a mode for cooking fried food, the amount of heating power is controlled so that the cooking container 1 is maintained at a predetermined temperature, or when the cooking container 1 is performing normal heating. When the temperature is abnormally high, the amount of heating power is suppressed or the heating is stopped to ensure safety so that there is no oil ignition. The heating control means 8 and the temperature detection means 5 may be integrated, and a DSP or a microcomputer is often used, but is not limited thereto, and may be a custom IC. .

  Here, the cooking vessel 1 is magnetically coupled to the heating coil 3 and is usually made of a magnetic material. Copper and aluminum, which are non-magnetic and low resistance metals, cannot be heated with a normal induction heating device, but recently, a method that can heat even a low resistance metal has been put to practical use. It may be a resistance metal cooking container. Moreover, when the diameter of the cooking container 1 is small, or when there exists a big gap between the top plate 2 and the cooking container 1, it is designed so that it cannot heat.

  The top plate 2 is a part that forms the appearance of the induction heating device, and is where the cooking container 1 is placed. The top plate 2 is made of heat-resistant tempered glass or the like, and since it is flat, it is excellent in terms of ease of cleaning and aesthetics, and is one of the advantages of the induction heating device.

  The infrared sensor 4 receives infrared rays emitted from the cooking container 1. A plurality of infrared sensors 4 may be provided. In the conventional induction heating apparatus, a contact type temperature sensor such as a thermocouple or a thermistor attached so as to be in contact with the lower portion of the top plate 2 is used. In that case, the upper part of the top plate 2 is warmed by the heat conduction and radiant heat of the part where the bottom part of the cooking vessel 1 and the top plate 2 are in contact, and the heat is conducted toward the lower part of the top plate 2, and the temperature is reduced. Will be measured. In this case, since the temperature at the bottom of the cooking container 1 is indirectly measured through the top plate 2, it depends on the size of the contact area between the cooking container 1 and the top plate 2, the heat capacity of the top plate 2, and the like. There existed a subject that the responsiveness with respect to the temperature fluctuation of the cooking vessel 1 was bad. However, in the case of the infrared sensor 4, since infrared rays from the cooking container 1 are directly received by the infrared sensor 4, cooking is not affected by the size of the contact area between the cooking container 1 and the top plate 2 or the heat capacity of the top plate 2. There is an advantage that it reacts immediately to the temperature fluctuation of the container 1.

  Thereby, for example, when heating is performed in a state where there is no cooked food in the cooking container 1, the temperature of the cooking container 1 rapidly increases. There is a safety device that prevents the cooking container 1 from reaching the ignition point of the oil because there is a possibility that it will ignite when the oil is dropped into it. In the conventional induction heating apparatus, since there is a delay with respect to the temperature fluctuation of the cooking container 1 as described above, ignition is prevented as a design having a sufficient margin. However, the function may function even when preheating the frying pan, and the usability may be deteriorated. However, when the infrared sensor 4 is used, it is not necessary to see a margin for a delay in the thermal response, so that such a situation can be avoided.

  The temperature detection means 5 converts the output of the infrared sensor 4 into a temperature. The energy received by the infrared sensor 4 is converted into a voltage, current, or frequency determined by the energy and output. The temperature detection means 5 converts these physical quantities into temperatures and uses them as information necessary for controlling the heating power. The temperature detection means 5 has a function of inputting a physical quantity of the infrared sensor 4, a calculation function of converting the physical quantity into temperature, and a function of outputting the converted temperature. The converted temperature information is sent to the heating control means 8, and various controls are performed according to the temperature.

  This method has no problem when the detection area of the infrared sensor 4 is entirely covered by the bottom of the cooking container 1 and the energy detected by the infrared sensor 4 is all infrared energy from the cooking container 1. However, if there is a part of the detection area of the infrared sensor 4 where the bottom of the cooking container 1 is not covered, disturbance light enters from that part, and the infrared sensor 4 receives the energy of the disturbance light. Since the energy of disturbance light is larger than the infrared energy radiated from the cooking container 1, the infrared energy from the cooking container 1 cannot be detected.

  In order to avoid such a situation, in the present invention, the cooking container 1 is calculated from the illuminance sensor 6 that detects the illuminance around the cooking container 1, the energy received by the infrared sensor 4, and the energy received by the illuminance sensor 6. The induction heating apparatus is provided with a cooking container detection means 8 for discriminating whether or not there is, and provided with a communication control means 10 for controlling the lighting for cooking 9 when the illuminance detected by the illuminance sensor 6 is low. .

  The illuminance sensor 6 is for detecting the illuminance around the cooking container 1. Although the illuminance sensor 6 has a characteristic that matches the human visual sensitivity, it does not have to be that particular.

  The cooking container detection means 8 determines the presence or absence of the cooking container 1 from the energy received by the infrared sensor 4 and the energy received by the illuminance sensor 6.

  The communication control means 10 is composed of an infrared light emitting element, and issues a command to the cooking light 9 by issuing an on / off signal of the light emitting element. On the other hand, the cooking light 9 is composed of a portion of the light 9a and a light receiving portion 9b that receives infrared light, and determines whether or not the signal received by the light receiving portion 9b is correct. In response, the lighting 9a is turned on or off.

  The detection method of a cooking container is demonstrated using FIG.

  In STEP1, first, the energy received by the infrared sensor 4 is measured. The measured value is V1.

  In STEP2, the energy received by the illuminance sensor 6 is measured. The measured value is V2.

  In STEP 3, the magnitude of V1 measured by the infrared sensor 4 and the determination value α are compared. The determination value α is the energy detected by the infrared sensor 4 when the infrared sensor 4 is placed in a dark state and does not receive the energy of disturbance light and the cooking container 1 is at a predetermined temperature (for example, 25 degrees). Set the value to the sum of the variation element and the margin.

  If V1> α, this means that it is receiving infrared energy that is emitted when the cooking container 1 is higher than a predetermined temperature, or is larger than the energy in the dark state due to the energy of disturbance light. It can be thought that it became.

  The predetermined temperature is 25 degrees, but may be any number as long as the temperature of the object is equal to or lower than the temperature at which the infrared sensor 4 can detect infrared energy.

  In STEP4, the magnitude of V2 measured by the illuminance sensor 6 and the determination value β are compared. The determination value β will be described with reference to FIG. The difference between the energy a received by the infrared sensor 4 when the infrared sensor 4 is placed in a dark state and the energy b received by the infrared sensor 4 when the infrared sensor 4 is placed in an environment with a certain illuminance γ. The illuminance is increased to a level at which (ba) can be detected, and β is set as a value obtained by adding a variation element and a margin to the illuminance γ when the energy of the infrared sensor 4 becomes b. When V2> β, there is sufficient illuminance around the cooking container 1 so that if the bottom of the cooking container 1 does not cover the detection area of the infrared sensor 4, It can be considered that the infrared sensor 4 is placed in a state where the light enters the detection area of the infrared sensor 4 as disturbance light, and the infrared sensor 4 receives the light to increase the received light energy.

  Since STEP5 has the conditions of V1> α and V2 <β, it can be seen that the surroundings are sufficiently darker than V2 <β, and it is not a situation in which ambient light can enter from the surroundings. Furthermore, it is considered that infrared energy from the cooking container 1 is received from V1> α. That is, since the bottom of the cooking container 1 covers the detection area of the infrared sensor 4 and the infrared energy from the cooking container 1 can be received, it is determined that the cooking container 1 is present and the cooking container 1 is heated. The temperature detecting means 5 can accurately calculate the temperature from the energy received by the infrared sensor 4. At this time, since the infrared sensor 4 has already received the infrared energy from the cooking container 1, it turns out that the cooking container 1 is high temperature.

  Since STEP6 satisfies the conditions of V1> α and V2> β, it can be seen that the surroundings are sufficiently brighter than V2> β, and ambient light can enter from the surroundings. It is considered that there is a possibility that light around the cooking vessel 1 enters as disturbance light and receives infrared energy from V1> α. That is, there is a possibility that the bottom of the cooking container 1 does not cover the detection area of the infrared sensor 4, and there is a possibility that the S / N ratio is deteriorated by light other than the infrared energy from the cooking container 1 and the temperature cannot be accurately detected. There is. Therefore, it is determined that there is no cooking container 1 in such a state, and control is performed so that heating of the cooking container 1 is stopped or the amount of heating power is suppressed.

  Or since the bottom part of the cooking container 1 has covered the detection area of the infrared sensor 4, and the cooking container 1 has become more than predetermined | prescribed temperature, the infrared sensor 4 may receive infrared energy. Since these cannot be distinguished from each other, the control may be such that the user of the induction heating device is notified that the presence or absence of the cooking container 1 cannot be determined.

  Since STEP7 is the same as STEP4, description is abbreviate | omitted.

  Since STEP8 is a condition of V1 <α, V2> β, it can be seen that the surroundings are sufficiently brighter than V2> β, and ambient light can enter from the surroundings. From V1 <α, it can be determined that the infrared sensor 4 is in a dark state. That is, although the ambient light may be received by the infrared sensor 4, the bottom of the cooking container 1 covers the detection area of the infrared sensor 4, so the ambient light is blocked. Since the cooking container 1 is determined to be present because the infrared energy from 1 can be received, the temperature detection means 5 can accurately calculate the temperature from the energy received by the infrared sensor 4 even if the cooking container 1 is heated. . At this time, since the cooking container 1 is low temperature, it turns out that infrared energy is not radiated | emitted.

  Since STEP9 has the conditions of V1 <α and V2 <β, it can be seen that the surroundings are sufficiently darker than V2 <β, and it is not a situation where ambient light can enter from the surroundings. From V1 <α, the infrared sensor 4 is the same as when it is placed in a dark state. That is, the infrared sensor 4 receives neither infrared energy from the cooking container 1 nor ambient light from the surroundings, but it is known that there is no disturbing light from the surroundings. The detection area may not be covered, and it cannot be determined that the cooking container 1 is present. Therefore, since the presence or absence of the cooking container 1 cannot be determined in such a state, the cooking illumination 9 is operated so that confirmation can be performed (STEP 10).

  Next, the control and operation of the cooking illumination will be described with reference to FIG.

  In STEP 5, a signal for turning on the cooking light 9 is output in STEP1. In response to the signal, the cooking light 9 is turned on in STEP2.

  In STEP 3, the energy received by the illuminance sensor 6 is measured. Let the measured value be V2 '.

  In STEP4, the magnitude of V2 'measured by the illuminance sensor 6 and the above-described determination value β is compared. Here, since the cooking light 9 is normally turned on, V2 ′> β is satisfied, and the illuminance around the cooking container 1 is sufficient. As described above, the bottom of the cooking container 1 is infrared. It will be in the state which can determine whether the detection area of the sensor 4 is covered.

  When V2 '> β, the process proceeds to STEP5, the energy received by the infrared sensor 4 is measured, and the measured value is set to V1'. In STEP 6, the magnitude of V1 'measured by the infrared sensor 4 is compared with the above-described determination value α.

  When V1 ′> α, that is, V1 <α until the cooking light 9 is turned on, and therefore the energy of disturbance light is received by turning on the cooking light 9. Therefore, it can be considered that the energy is larger than the energy in the dark state. That is, it can be considered that there is no cooking container (STEP 7).

  On the other hand, when the result determined in STEP 6 is V1 ′ <α, the lighting for cooking 9 is turned on, and the surroundings are sufficiently bright with V2 ′> β, and ambient light can enter from the surroundings. Nevertheless, it can be determined that V1 <α and the infrared sensor 4 is in a dark state. That is, although the ambient light may be received by the infrared sensor 4, the bottom of the cooking container 1 covers the detection area of the infrared sensor 4, so the ambient light is blocked. Since the cooking container 1 is determined to be present because the infrared energy from 1 can be received, the temperature detection means 5 can accurately calculate the temperature from the energy received by the infrared sensor 4 even if the cooking container 1 is heated. . At this time, since the cooking container 1 is low temperature, it turns out that infrared energy is not radiated | emitted (STEP8).

  In addition, when the result determined in STEP 4 is V2 ′ <β, the cooking illumination 9 is normally turned on, so it should be V2 ′> β, but this is not the case. It will be in the state which cannot judge the presence or absence of the cooking container 1 (STEP9).

  Possible causes are some troubles such as the lighting 9 for cooking is not lit or the illuminance sensor 6 cannot be measured accurately due to, for example, a communication failure between the infrared light emitting element and the light receiving element. It can be presumed that Accordingly, the display means notifies the user of the induction heating device that the presence or absence of the cooking container 1 cannot be determined (STEP 10).

  In this way, the conventional infrared sensor 4 alone has a problem that the accurate temperature cannot be measured when ambient light enters, but the cooking container detection means 7 as in the present invention. Therefore, even when the ambient illuminance is low, the presence or absence of the cooking container 1 is determined, and it is determined whether or not an accurate temperature can be detected. It is possible to provide an induction heating device that can avoid dangerous situations such as deformation and breakage, or ignition of oil, which can provide benefits to the user.

  The temperature detection means 5, the cooking container detection means 7, and the heating control means 8 are each often a DSP, a microcomputer, or the like, but are not limited thereto, and may be a custom IC. These functions may be shared by a single microcomputer or the like.

  For the indication that the presence or absence of the cooking container cannot be determined by the display means, for example, numerals or alphabets may be used as a symbol indicating an error, or a dot liquid crystal may be used for the display means and characters may be used. Direct display is also possible.

  The cooking light 9 does not need to be turned on after cooking for a while, for example, when the lighting 9 is turned on by the communication control means 10 due to insufficient ambient illuminance. In addition, when a predetermined time (for example, about 5 minutes) elapses after the heating operation is stopped, it is possible to turn off the lighting for cooking 9 by the communication control means 10 to prevent unnecessary power consumption of the lighting. is there.

  Further, when the illumination control is not insufficient and the communication control means 10 does not send an instruction to turn on the cooking light 9, the instruction to turn off the cooking light 9 is not sent even after the heating operation is finished. Thus, for example, it is possible to prioritize the intention when the user manually controls the cooking light 9 and to improve usability without turning off the light.

  As described above, in the induction heating device according to the present invention, even when the ambient illuminance is insufficient, the presence or absence of a cooking container, which was a problem in detecting temperature with an infrared sensor, is detected, and the cooking container is It is safe to control the cooking container to a temperature that does not cause deformation, damage, oil ignition, etc. by making it an induction heating device that continues normal heating only when it can be reliably measured and the temperature can be measured accurately Therefore, it is possible to realize an induction heating device that is easy to use.

Schematic block diagram of the induction heating apparatus in Embodiment 1 of the present invention Flowchart of determination in cooking container detection means Diagram showing judgment value design Diagram showing infrared energy and visible light wavelength Flow chart of control in cooking lighting and determination in cooking container detection means Schematic configuration diagram of a conventional induction heating device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cooking container 2 Top plate 3 Heating coil 4 Infrared sensor 5 Temperature detection means 6 Illuminance sensor 7 Cooking container detection means 8 Heating control means 9 Cooking illumination 10 Communication control means 11 Display means 12 Light guide means

Claims (4)

A cooking container for heating food, a top plate on which the cooking container is placed, a heating coil for generating an induction magnetic field to heat the cooking container, and infrared rays radiated from the cooking container through the top plate An infrared sensor for detecting the temperature, a temperature detecting means for converting the temperature of the cooking container from the energy received by the infrared sensor, an illuminance sensor for detecting the illuminance around the cooking container, and light reception by the infrared sensor Cooking container detection means for determining the presence or absence of the cooking container from the energy received and the energy received by the illuminance sensor, and the high frequency current of the heating coil is controlled by the detection result of the cooking container detection means and the temperature information of the temperature detection means. Heating control means for controlling the heating power amount of the cooking container, cooking lighting for illuminating a cooking place, and the adjustment Communication control means for performing communication and control with the lighting for lighting, and when the value detected by the illuminance sensor is equal to or less than a predetermined value, the communication control means turns on the cooking lighting. Induction heating device. The induction heating apparatus according to claim 1, wherein when the heating control unit finishes heating the cooking container, the communication control unit turns off the cooking light after a predetermined time has elapsed. If the control for turning on the cooking light is not performed by the communication control means, the cooking light is not turned off by the communication control means even if the heating to the cooking container is finished by the heating control means. The induction heating apparatus according to claim 1 or 2, which is configured. Even if the communication control means has a display means and the control for lighting the cooking light is performed, if the value detected by the illuminance sensor is not more than a predetermined value, the display means indicates the presence or absence of the cooking container. The induction heating device according to any one of claims 1 to 3, wherein a display indicating that detection is impossible is performed.